Adding go lint to more modules (#738)

tap/extensions/kafka/compression.go

@@ -1,8 +1,6 @@
 package kafka
 
 import (
-	"errors"
-
 	"github.com/segmentio/kafka-go/compress"
 )
 
@@ -12,19 +10,3 @@ type CompressionCodec = compress.Codec
 
 // TODO: this file should probably go away once the internals of the package
 // have moved to use the protocol package.
-const (
-	compressionCodecMask = 0x07
-)
-
-var (
-	errUnknownCodec = errors.New("the compression code is invalid or its codec has not been imported")
-)
-
-// resolveCodec looks up a codec by Code()
-func resolveCodec(code int8) (CompressionCodec, error) {
-	codec := compress.Compression(code).Codec()
-	if codec == nil {
-		return nil, errUnknownCodec
-	}
-	return codec, nil
-}